Fuzz testing module

This adds a module for fuzz testing distarray. It still needs some work, but there are a lot of directions this could go from here so please tell me what kind of tests/capabilities you would like to see.

To try it just run the `_test_fuzz.py` module. It creates some number of random distarrays and tests them.

`rand_distarray.py` is a module for generating random distarrays.
`fuzzy_test.py` is a module for testing random distarrays.